Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
thuoc ma » hoc ma, duoc ma
tu sach » thu sach, su sach, te sach
tang xa » trang xa, tang ma, lang xa
ma hanh » va hanh, da hanh, na hanh
vai cua » dai cua, hai cua, lai cua
vi cua » di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thuat song)) kho tang xa hoi. hieu van nam thuoc ma hanh ((vi cua) OR (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat song)) kho tang xa hoi. hieu van nam thuoc ma hanh ((vi cua) OR (vai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuat song)) kho tang xa hoi. hieu van nam thuoc ma hanh ((vi cua) OR (vai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat song)) kho tang xa hoi. hieu van nam thuoc ma hanh ((vi cua) OR (vai cua)) tre*.